Modern user devices such as phones (e.g., smartphones), tablets, notebooks, electronic readers and the like typically include, in addition to wireless communication capabilities, one or more sensors that can detect and/or infer the context of the device and, by extension, contextual information of the user. One example is the use of a position or location determining sensor such as one embodied as a global positioning satellite (GPS) receiver and sub-system.
In addition to the large amount of personal data stored on these user devices (sms logs, call logs, contacts list, etc.) many sensors can be used to infer the location, context, personal habits, etc. of the user. All of this information is exposed to at least two privacy threats: (A) third party applications that the user installs, but does not necessarily trust; and (B) the possibility that this information will be shared or published by the user himself, unaware of the privacy threats.
One problem that arises relates to the control of the user information to provide the user with a desired degree of privacy.